The present invention is directed to the use of novel recombinant DNA molecules in which an avian long terminal repeat (LTR) is ligated to the bovine growth hormone (BGH) gene, and co-transformed into stable mouse fibroblast cell lines containing the recombinant genetic material integrated into the mouse cell genome. These mouse cells can be encapsulated into hollow fibers and implanted into animals (e.g., subcutaneously, intradermally or intraventricularly, etc.), thereby producing circulating bovine growth hormone (BGH).
Copending application Ser. No. 609,923 filed May 14, 1984, filed by the same inventors and assigned to Merck & Co. Inc., discloses and claims the preparation of the plasmids and the mouse cell lines producing BGH.